#include <stdio.h>

int main() {
	int i, n;
	double m = 1, sum;
	for (n = 1; n <= 20; n++) {
		m = 1;
		for (i = 1; i <= n; i++) {
			m = m * i;
		}
		printf("%d!=%.1f\n", n, m);
		sum = sum + m;
	}
	printf("sum=%.1f", sum);
	return 0;
}